Means for automatic locking and releasing rechangeable work guiding cams in zig-zag sewing-machines



May 9, 1961 A. MORO MEANS FOR AUTOMATIC LOCKING 2,983,531 AND RELEASINGRECHANGEABLE WORK GUIDING CAMS IN ZIG-ZAG SEWING-MACHINES Filed Nov. 30,195e 2 Sheets-Sheet 1 Inventor LLI Harney A. MORO May 9, 1961 2,983,53 lGEABLE 2 Sheets-Sheet 2 Filed Nov. 30, 1956 www o m WM no mwA hm. w AJ.vwm moi v. B l) t w l... I M

rates 2,983,531 Patented May 9, 1961 fcc 2,983,531 MEANS FOR AUTOMATICLOCKING AND RE- LEASING RECHANGEABLE WORK GUIDING CAMS 1N ZIG-ZAGSEWING-MACHINES Antonio Moro, Milan, Italy, assgnor to S.p.A. FratelliBorletti, Milan, Italy 'In modern sewing machines of the zig-zag typecams are used which are adapted to effect cyclic automatic displacementsof the needle bar transversely and of the feed dog for the purpose ofobtaining automatically cyclic ornamental seams.

`Said cams must be changed every time that it is desired to perform bymachine a seam different from the previous one; and in the machines ofdomestic kind it is necessary that the operator, even the less skilled,may be able to effect the change of the cam in a rapid, simple andintuitive manner, without the risk of causing damage to the machine ormounting the cam in a wrong way.v

The device for automatic locking and releasing of said cams, which`forms the object of the present invention, responds to theserequirements.

Said device comprises releasable clutch means for the cam, actingagainst the cam expulsion means, both carried by supports driven inrotation by the shaft of the cam. The device is characterized in thatsaid releasable clutch means consists of a pair of spring hook leverspivoted behind the mounted cam, in diametrically opposed points of therelative support, said levers having projections on their free endsbearing against the front face of the cam in such a manner as to make itpossible to disengage them by the direct action of two lingers, whilethe cam expulsion means consist of springs placed behind the cam itself,between the latter and the relative support.

It is thus suicient to simply push the cam towards its applicationposition on the rotatable shaft, when the latter is free, so that thecam settles in a correct position and, vice-versa, it is sufficient,when the cam must be removed, to approach both levers to each other byacting on their free ends with two fingers for leaving the springsplaced behind the cam free to push the cam outwards in such a manner asto make it possible to extract it very easily from its shaft.

`In a preferred embodiment, the hook levers are pivoted upon a sleevefixed, in an easily removable manner, on the front of a cam-supportingliange, projecting from a means driven, in rotation, by the cam-carryingshaft, upon which the sleeve is so centered as to be possible to composethe device according to the invention, independently of the machine onwhich it has to be applied, in a group standing by itself, apt to berapidly and easily applied on the machine, if necessary. The hook leverscan however be also directly mounted on said flange.

Examples of these different embodiments are illustrated, in applicationon a zig-Zag sewing machine, in the accompanying drawings, where:

, Fig. 1 is a longitudinal section of an embodiment of the invention, ofwhich Fig. 2 is a front view with cam partially broken in order to showthe expulsion spring placed behind said cam;

iFig. 3 is a view similar to the one in Fig. 1 of an embodiment of theinvention, and

Fig. 4 is a perspective view of the different detached members of Fig. 3being disposed in mounting order.

` Fig. 5 is a perspective view of an embodiment of the cam-supportingange.

According to the embodiment of Figs.. 1 and 2, shaft 1, carrying cam 2provided with two radial diametrically opposed openings 3 and 4, iscaused to rotate, through a gear or belt transmission (not shown), bythe driving shaft of the zig-Zag sewing-machine with a determinedspeed-ratio.

On the end `of shaft 1 disposed towards the outside of the machine frame5 is fixed hub 6 having a disc flange 7 designed to carry cam 2, withthe interposition of a flat spring S, which pushes the cam outwards.Flange 7 has two openings 9 and 10 corresponding to openings 3 and 4 ofcam 2, through which pass the two small levers 11 and 12 with outwardends shaped as teeth having plain surfaces 13 and 14, adapted to engagethe front surface 32 of cam 2. The two levers 11 and 12 are mounted onpivots 15 and 16 respectively, about which they can swing.

The two pivots 15 and 16 are held by suitable recesses 17, 18 formed ina ring 19 firmly fixed lon llange 7.

The two levers 11 and 12 are pushed outwards by springs 21, 22respectively, which in fact make the lever action elastic. Thedisplacement of 4lever 11 is limited on the outside by side 23 of spring8, said spring being adapted to be displaced and adjusted according toarrow 24 by lunscrewing screw 25, which locks it; the similardisplacement of lever 12 is limited by means of the small adjustableplate 26 adapted to be locked by screw 27. In order to allow both spring8 and plate 2d to be displaced, the holes, through which the respectivescrews 25 and 27 pass, are oblong.

Cam '2 is placed and locked in correct position by introducing it onshaft 1, by which it is centered, and then by causing its eccentric hole29 to coincide with pin 36 fixed to flange 7, said pin determining theexact angular orientation of the cam. When the cam is in correctposition, in its seat, it keeps wings 23 and .28 of spring 8 pressed,said wings maintaining the cam constantly pushed outwards.

The operation and use of the device can now be commenced.

Suppose that a cam 2 is already mounted and it is wished to change itwith another, it is suflicient to press with two lingers the smalllevers 11 and 12 according to arrows 31 and 31', thus overcoming theresistance of springs 21 and 22; plain surfaces 13 and 14 of levers 11and 12 will then leave the front surface 32 of cam 2 so that the latter,pushed by the two wings 2S and 2S of spring 8, will slide out free to beremoved.

The two small levers 11 and 12 will stop against the stops 23 and 26predisposed in such a position that the ends 33 and 34 of said leversmay be within a circumference with a diameter suitably smaller than theone of surfaces 3S-36 of the corresponding openings 3 and 4 of cam 2.

For mounting a new cam it will then be suflcient to Introduce the cam onhub 6 disposing hole 29 on pin 3G.

Surfaces 35 and 36, sliding on the inclined surfaces 37-38, will causelevers 11 and 12 to be depressed downwardly so that the cam can bepushed inwardly, thus pressing wings 28-28 of spring 8, till cam 2assumes its operating position.

Levers 11 and 12, pushed outwards by springs` 21 and 22, will lock cam 2in said position, by their plain surfaces 13 and 14.

In the embodiment according to Figs. 3 and 4, flange 107 with hub 106 isfixed on the rotating shaft 101 as described for the first embodiment.On flnage 107 are provided plain zones 139 which serve as supports forthe demountable cam 102. The locking hook levers 112 and 133 are mountedby means of pivots 141i on the small ears of a sleeve 141, which isadapted to be introduced on hub 106 and xed by screws 142, said screwsentering holes 143 of sleeve 141 and being screwed in the threaded holes144` of ange 107.

Hook levers 112 and 133 are guided in hollows 145 of sleeve 141 andpushed outwards by springs 121 and 122.

The limitation of outward movement of hook levers 112 and 133, when thecam is removed, is effected by ring 146, which is centered on band 147ofsleeve 141 and is held between projection 148 and plain surface 149 offlange 107. Ring 146 can, if desired, be substituted by two small plates246 (see Fig. 5) adjustably mounted on flange 107 supporting the camnear leversl 112 and 133, and cooperating with said levers by means oftheir edges.

The axial push of the cam outwardly is effected by two springs 128 whichare held between plain sectors 151 and plain surface 149 by screws 142passing through the respective holes 152.

The ends 153 of springs 128 cause cam 102 to move in an outwarddirection, when hooks 112 and 133 are pushed towards axis 101, insimilar manner to the one described for the first embodiment.

As the teeth of hook levers 112 and 133 lock cam 102 in its seat bypressing against the periphery of hole 154, the advantage is obtainedthat cam 102 can have more than one reference hole 155 which mustcoincide with pin 156 located centrally on support zones 139;consequently cam 102 can be inserted into as many angular positions asare the number of holes 155 provided in the cam, so as to allow one camvarious different angular positions and therefore as many combinationsfor different cyclic seams.

The operation of mounting and removing a cam takes place in the samemanner as the one described for the other embodiment.

It is understood that the construction and disposition particulars ofthe device can vary from those represented in the drawings and abovedescribed, the device always remaining within the purview of theinvention.

Thus, for instance, not only instead of two locking and unlocking leversit can be used for the same aim only one lever or more than two leverswith relative springs, as well as for pushing the cam out of its seatmany springs can be substituted to the single or double one, establishedin any suitable manner on the camsupportingilange, but also saidsprings, instead of being of a flat kind, can be of any other suitablekind, for instance spiral springs. On the other hand, the cam lockingand unlocking lever or levers instead of being rigidly pivoted by oneend and made elastic by a spring, can be levers formed by a flexibleplate xed by one end and provided with a hooking tooth at the oppositefree end.

Other modifications not altering the invention at all can be easilyconceived by those skilled in the art.

What I claim is:

1. In a zig-zag sewing machine, improved means for the automatic lockingand releasing of rechangeable cams comprising releasable clutch meansfor the cam acting against cam expulsion means, a cam shaft, supportmeans carried by and driven in rotation by the shaft and supporting saidclutch means and cam expulsion means, and said releasable clutch meansconsisting of a pair of spring hook levers pivoted behind the mountedcam on diametrically opposed points of the support, said leversprojecting with their free ends from the front face of the cam in such amanner as to make it possible to disengage them by the direct action oftwo fingers', while the cam expulsion means consists of springs placedbehind the cam itself, between the latter and the support, orientingmeans on said support for engagement with corresponding means on the camto orient the cam with respect to said shaft, and adjustable limitingmeans to limit the outward movement of said levers.

2. A zig-zag machine as in claim 1, wherein said hook levers are pivotedon a ring fixed behind the ange of a hub driven in rotation by thecam-carrying shaft, the cam being supported by said flange with theinterposition of spring means for its expulsion from its seat, said hooklevers crossing corresponding radial openings of both the ange and thecam, in order to engage by their hook the front faces of the cam underthe action of springs placed in radial openings of the hub.

3. A zig-zag machine as in claim 2, wherein said spring means for theexpulsion of the cam from its seat consist of a horse-shoe-shaped lflatspring, adjustably fixed to said ange, so as to act by a portion of itsinner edge as a stop for limiting the opening of one of said hooklevers, when the cam is removed, the stop of the other lever consistingof the edge of a small plate adjustably fixed on the cam-supportingflange in a position diametrically opposed to the one fixing the spring.

4. A zig-Zag machine as in claim 1, wherein said adjustable limitingmeans consists of the edge of a small plate adjustably fixed on thesupport means supporting the cam, a plate being provided for each lever.

5. In a zig-zag sewing machine as set forth in claim 1, said supportmeans comprising a sleeve removably fixed on a cam abutting flange, saidsleeve having a pair of diametrically opposed openings therein, said camabutting flange positioned rearwardly of said sleeve and drivinglyconnected with said shaft, said levers each being pivoted in one of saidopenings and extending generally axially forwardly, said sleeve having aradially extending hole therein connected with each opening, springs insaid holes yieldingly urging said levers outwardly, and spring means forthe expulsion of the cam from said support means.

6. A zig-zag machine as in claim 5, wherein said spring means for theexpulsion of the cam from its seat consist of a pair of at springsinterposed between said flange and said sleeve, and a pair of screwsfixing the sleeve to the flange and each penetrating one of said ilatsprings.

7. Mechanism for locking and releasing exchangeable cam discs forzig-zag sewing machines comprising a shaft, a support on said shaft, apair of hook levers pivotally mounted on said support at diametricallyopposite points, said levers extending forwardly, a cam disc mounted onsaid shaft forwardly of said support and having a pair of diametricallyopposed apertures therethrough, the free ends of said levers extendingthrough said apertures, each hook lever having a hook surface extendingtransversely of the axis of the shaft and engaging the front surface ofthe cam disc and forwardly projecting finger engageable parts in advancethereof, orienting means on said support and said cam disc, spring meansmounted on said support for urging the cam disc away from said support,further spring means mounted on said support for urging the hook leversradially outwardly, and adjustable limiting means to limit the outwardmovement of said levers.

References Cited in the le of this patent UNITED STATES PATENTS 173,126Little Feb. 8, 1876 285,303 Patten Sept. 18, 1883 505,490 StanbroughSept. 26, 1893 653,397 Pettijohn July 10, 1900 812,784 Clay et al. Feb.13, 1906 2,116,735 Stevens May 10, 1938 2,251,470 Stacey .Aug. 5, 19412,615,643 Barsam Oct. 28, 1952 2,617,165 Stanley et al Nov. 1l, 19522,652,989 Ripley Sept. 22, 1953 FOREIGN PATENTS 992,267 France July 4,1951 557,113 Great Britain Nov. 4, 1943

